10 reasons castors fail and how to avoid them

Sometimes the wheels come off and castors fail. Although in almost all cases, it’s not the actual wheels that come off. In fact, more often than not it’s not the fault of any of the component parts.

Castors may only be a small part of the grand design, but they're integral and there are many outside factors that can cause them to fail. And when castors fail, the whole design stops working. That means unplanned downtime, loss of productivity and a hit to the business bottom line. A castor failure could even result in employees being injured in the workplace.

Consequences of castor failures

Any industry that uses castors would be seriously affected by a component fail. In the medical industry a castor failing to absorb shock on a patient bed could result in that patient being paralysed. Consider that a castor failing to steady expensive hospital equipment could cost the NHS thousands of pounds. In the manufacturing industry, a failing castor could halt a key area of the production process, affecting the onward supply chain and future business. In the entertainment industry, a castor failing to provide a smooth, silent camera track over the floor is guaranteed to spoil the show.

The list goes on.

So how is this happening? The good news is that most castor failures are avoidable if you understand the pitfalls. So let’s take a look at 10 of the most common reasons for castor failures and how to avoid them in your application.

10 reasons castors fail and how to avoid them

1. Extreme temperatures

Industrial castors used at temperatures exceeding 1000°F can cause the material to fail. Softer materials like polymers and rubbers can flat spot or even melt. Avoid extreme temperatures to secure the castors.

Avoid by using temperature-resistant materials, such as hard-wearing phenolic resin or high-temperature rubber wheels. These materials can typically stand up to temperatures ranging from -40° to +280°C.

2. Speed

Time is money, but running castors at speeds they’re not designed for can result in detrimental impact forces and overheating.

Avoid by finding out the speed at which the castor will be used in your application and selecting a castor with a speed capacity that's up to the job. Speed capacity is an important factor to consider.

3. Overloading

All castors have a capacity rating. If the load capacity exceeds this rating, the castors will fail. Load capacity is one of the most important factors. Be aware of the capacity rating of your castor materials.

Avoid by calculating the load capacity for each wheel. Simply divide the combined weight of equipment and maximum load by the number of castors to be used. Then to be on the safe side, choose a castor with a higher capacity than your calculation to allow for shock loads, rocking or poor floors. These methods can help you to secure your castor and be in the limits of load capacity. Avoid load capacity exceeds to improve the performance and security of your application.

4. Uneven loading

If one castor is made to carry a significantly higher proportion of the load, it can lead to premature wear and complete failure. Consider load distribution to equalise the load capacity.

Avoid uneven loading by taking the time to understand the load distribution of the castors and apply this to the castor design. If there is an uneven loading case, fix the issue with load distribution.

5. Impact loading

This is when a castor hits a large obstacle and experiences the associated g-forces, causing the castor to bear a load higher than its capacity rating.

Avoid by considering the use of spring-loaded or shock-absorbing castors.

6. Wrong bearings

One bearing type does not suit all. Choosing a type that’s not suited to an application experiencing extreme temperatures, humidity, liquids, corrosives or impacts will increase the risk of premature castor failure.

Avoid by matching the right bearing to the appropriate castor for your application, taking into consideration bearing material, shape and accessibility for maintenance. Wrong bearings can effect the performance and also may be a reason to castor fails.

7. Environmental

In addition to extreme hot and cold temperatures, wet environments, corrosives and debris can take their toll on certain castor materials – where they’re well suited to some but not others. Environmental factors are more important factors when it comes to castor failures. Avoid wet environments, corrosives and other environmental factors to not face with complete failure.

Avoid by knowing what’s in your application’s environment and then specifically selecting the castor material that’s best suited.

8. Excess swivel offset

A design flaw can result in too big a distance between the centre of the axel and the centre of the kingpin or main rivet. This could cause the legs of the yoke to break away from the swivel when a load is applied.

Avoid by ensuring the design and engineering teams collaborate to find the optimum balance between a large enough offset for ergonomic efficiency and a short enough offset to ensure joint strength.

9. Terrain

Rough terrain such as rough, uneven or sloping surfaces can shorten the lifespan of a castor, particularly soft wheels.

Avoid by ensuring the castor has a shock-absorbing element to it.

10 Brinelling

This is the wear that is pressed by the ball bearings in the swivel head into the hard cap. It affects the performance of the swivel of the castor by increasing the swivel force.

Avoid by using the Brinell hardness test as part of your calculations to ensure you use the right materials.

Download free CADs and try before you buy

Free CADs are available for most solutions, which you can download. You can also request free samples to make sure you’ve chosen exactly what you need. If you’re not quite sure which solution will work best for your application, our experts are always happy to advise you.

Whatever your requirements, you can depend on fast despatch. Request your free samples or download free CADs now.

Questions?

Email us at sales@essentracomponents.co.uk or speak to one of our experts for further information on the ideal solution for your application 0345 528 0474.